The invention relates to an electric lamp provided with a lamp envelope and a lamp bowl of a synthetic material which is connected at one end to the lamp envelope and has a lamp cap at its other end. A lamp of this type is known from U.S. Pat. 4,383,200.
The known lamp is a compact low-pressure mercury vapor discharge lamp with a cap at one end and having a glass lamp envelope accommodating a hook-shaped fluorescent discharge tube which is sealed in a gas-tight manner. Such a lamp is used as an alternative to an incandescent lamp for general illumination purposes. Furthermore, the lamp includes an electric stabilization ballast and a starter which are partly accommodated in the space bounded by a slightly tapered lamp bowl of synthetic material.
The lamp bowl of the said lamp is screwed onto the lower side of the lamp envelope, for which purpose the lamp envelope has a screwthread or special projections for fixation.
In the British published Patent Application 2,154,057 corresponding to U.S. Pat. No. 4,645,967. an electrodeless low-pressure mercury vapor discharge lamp is disclosed in which the glass bulb-shaped envelope of the lamp vessel is secured to a lamp bowl of synthetic material by means of a clamping joint.
It is a time-consuming and rather complicated matter to realize the joint between the lamp bowl and the lamp envelope during the manufacture of the lamps, notably in a bulk-manufacturing process of these lamps.